PROJECT SUMMARY This exploratory R03 project will focus on patient safety in hospitalized children, especially those with overweight or obesity. Hospitalized children experience high rates of adverse events, which are estimated to cause 4,400 deaths and >$1 billion in costs annually. Despite the fact that 16.9% of American youth now have obesity, little is known about adverse events in this population. Overweight and obesity are associated with poor outcomes in pediatric inpatients, such as increased mortality, length of stay, and hospital charges, but the mechanisms underlying these associations are unknown. Adverse events can be identified by voluntary event reporting (VER), which may be affected by provider weight bias, or by patient chart review using a trigger tool, which identifies 10 times more events than VER alone. The Global Assessment of Pediatric Patient Safety (GAPPS) trigger tool has recently been shown to reliably detect adverse events in a variety of institutions with good agreement between reviewers. In this project, adverse events occurring in 900 hospitalized pediatric patients ages 2-18 years will be identified using the GAPPS trigger tool with manual chart review and using the hospital VER system. Adverse event incidence, type, preventability, and harm score will be compared by patient body mass index category (underweight, healthy-weight, overweight, and obesity) in Specific Aim 1. The incidence and types of harm identified by VER system versus GAPPS trigger tool will be compared by patient body mass index category in Specific Aim 2. The hypotheses are that (1) patients with overweight and obesity will have a higher incidence of adverse events than healthy-weight children, after adjusting for age, sex, race/ethnicity, insurance status, and medical complexity; and (2) fewer events in patients with overweight and obesity will be identified by provider voluntary reporting, compared to the GAPPS trigger tool. This project, led by a New Investigator, has the potential to provide important insights into the poor outcomes documented for hospitalized children with obesity, and the utility of different measures for adverse event identification in this population. Given the continued high prevalence of obesity, this work has clear potential for reproducibility elsewhere to achieve the goal of improved hospital safety for the rapidly growing number of pediatric inpatients with overweight and obesity.